Question

 

 

làm phép tính

1/1.2+1/2.3+1/3.4+ ... +1/98.99+1/99.100

Answer 1

`1/( 1.2 ) + 1/( 2.3 ) + .......+1/(99.100)`

`= 1-1/2+1/2-1/3+.....+1/99-1/100`

`=1-1/100`

`=99/100`

Answer 2

=1-1/2+1/2-1/3+...+1/99-1/100

=1-1/100=99/100

Answer 3

\(=\dfrac{1}{1.2}+\dfrac{1}{2.3}+....+\dfrac{1}{99.100}\)

\(=1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+...+\dfrac{1}{99}-\dfrac{1}{100}\)

\(=1-\dfrac{1}{100}=\dfrac{99}{100}\)